Chap 12 Microscopic Analysis of Urine

• Microscopic examination of urine

  Important especially when positive results are obtained on the dipstick
• Microscopic examination of urine

  1. Mix the specimen

  2. Pour 12ml of urine in centrifuge tube

  3. Centrifuge 1200-2000 RPM

  4. Wet mount

  5. Observe under microscope
• Urine sediment


  • Obtained by centrifugation of urine
  • Cells tend to deteriorate when stored at RT (but can be delayed by refrigeration)
• Normal findings in microscopic urine examination

  • Squamous epithelial cells (especially in women)
  • Occasionally WBC/RBC
  • Few bacteria (contamination)
  • Rare hyaline cast
• Squamous epithelial cells


  Improper collection (non-pathologic)<|>Renal tubular damage (pathologic)<|>Upper UTI (pathologic)<|>Glomerular dysfunction (pathologic)
• Abnormal findings in microscopic urine examination

  • RBC (hematuria)
  • WBC (neutrophil)
  • Renal epithelial cells
• Bacteria


  Moved as opposed to Brownian movement
• Yeast


  Smaller than RBC but may appear similar (add acetic acid to distinguish)
• Protozoa


  Trichomonas vaginalis-frequent parasite found
• Casts


  Formed by precipitation of mucoprotein secreted by epithelial cells lining distal convoluted tubule<|>Formation of cast indicates temporary blocking of renal tubules
• Types of casts


  • RBC cast
  • WBC cast
  • Hyaline casts
  • Granular casts
  • Fatty acid casts
  • Waxy casts
• RBC cast


  Show the presence of RBC in protein matrix
• WBC cast


  Signify infection (pyelonephritis)
• Granular casts


  Result from cellular breakdown within the cast/renal tubule
• Crystals found in urine

  • Calcium oxalate
  • Uric acid
  • Cystine
  • Sulfonamide
  • Amino acid (tyrosine)
  • Triple phosphate
• Calcium oxalate crystal


  May indicate hypercalcemia
• Uric acid crystal


  Diamond-shaped (breakdown of tissue cell-gout)
• Cystine crystal


  Cystine replace uric acid in kidney causing kidney/liver damage (hereditary)
• Sulfonamide crystal


  Mechanical destruction of tubules (serious conditions)
• Amino acid (tyrosine) crystal


  Forming needles arrange in sheaves (liver disease)
• Triple phosphate crystal


  Coffin-lid appearance (normal or alkaline urine/UTI)
• Amorphous crystal


  Appear of aggregates of finely granular material without defining shape<|>Ex: urates-Na, K, Mg, Ca (acidic urine-yellow-brown)<|>Phosphate (alkaline urine-similar appearance but lack of colour)
• Healthy individual often has few crystal in their urine
• Examination should relate with physical & chemical properties
• For RBC & WBC, result will be reported as high power field (HPF) - example: 5-10 RBC/HPF
• For cast may be reported as low power field (LPF) - example: 5-10 hyaline cast/LPF
• Scan under microscope (semi-quantitative: rare, few, moderate, many,1+,2+,3+)